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On removing the pallium, it will be noted that there are 
no lateral ventricles, but a large single median prosocoele. 
In the floor of this are raised up the large corpora striata 
separated dorsally by a wide fissure, but connected below 
by the anterior commissure, and constituting the solid 
cerebral hemispheres of older authors. ‘These are con- 
siderably smaller than the optic lobes, and the dorsal 
surface of each is marked by a somewhat complex furrow 
(“sulcus ” of former authors—see fig. 30). In front of 
and below the striata are the olfactory bulbs, from which 
the olfactory nerves originate. ‘The left is smaller than 
the right. 
On the ventral surface of the brain the most notice- 
able structures are the appendages of the “tween-brain. 
‘The lobi inferiores are a pair of large bean-shaped bodies 
opposed by their median surfaces. In the middle line 
immediately in front of these is the spherical pituitary 
body. The apposition of the pituitary body and lobi 
inferiores is not complete, and a triangular space is left 
by which there emerges on to the ventral surface of the 
brain the red thin-walled saccus vasculosus. This is at 
its origin a very narrow tube, but 1t expands and passes 
straight backwards in the middle line over the opposed lobi 
inferiores. It is dilated behind, and ends blindly shghtly 
posterior to the hinder border of the lobi inferiores. In 
the adult the pituitary body (hypophysis cerebri) and 
saccus vasculosus are essentially glandular organs receiv- 
ing a marked nervous supply from the infundibulum. 
According to most recent authors the saccus at least 
“probably forms part of a mechanism for secreting, or 
otherwise controlling the pressure of, the cerebro-spinal 
fluid. It may affect the heart beat and blood pressure by 
way of the vagus” (J. B. Johnston). 
The crossing of the optic nerves is very obvious in the 
